SU1376234A1 - Electrolytically decoupled d.c. voltage amplifier - Google Patents

Abstract

The invention relates to a measurement technique, and can be used as an input normalizing, analog information amplifier of various sensors. The purpose of the invention is to reduce the dynamic error when working with pulsed signals, the DC amplifier contains two channels of 1.2 amplification, an additional isolation transformer (PT) 30, an additional modulator 11 and an output adder 17. Channel 1 consists of an input amplifier 3, modulator 4, PT 5, demodule. 6, a generator of 7 clock pulses, a low pass filter 8 and an amplifier 9 of direct current. Channel 2 consists of operational amplifiers 12, J3, galvanic isolation 34, made on the optocoupler, and feedback resistors 15.16. Channel 2 and input amplifier 3 of channel 1 have the same gain factor. Because winding PT 5, 10 included met, the input signal passing through the channel 2, the input amplifier 3 and acc. modulators .11,4, is compensated for, PT 5. As a result, channel 1 does not participate in the transmission of the input signal and the output of the device will only be voltage proportional to the output signal of channel 2. In the absence of the output signal of channel 2, the bias voltage in the secondary winding PT 5, the modulating voltage proportional to the bias voltage of channel 2 is applied to the Vits It is fed to the adder J7. 1 il. (C (L

Description

The invention relates to measuring equipment and can be used as an input normalizing amplifier of analog information of various sensors with voltage output. direct current, for example, strain gauges, galvanometers of control equipment, position sensors of controls, automation, etc. : jq

The purpose of the invention is the reduction of dynamic error when working with pulsed signals.

The drawing shows a structural electrical diagram of the proposed 15th DC voltage amplifier, DC amplifier with galvanic isolation contains. the first 1 and second 2 gain channels, the first channel 1 consisting of 20 input amplifier 3, a modulator 4, an isolation transformer 5, a demodulator 6, a clock generator 7, a low-pass filter 8 and a direct current amplifier 9, an additional 25 isolation transformer 10, an additional modulator 11, the second channel 2 consisting of the first 12 and second 13 operational amplifiers, a galvanic isolation element 14 made on an optocoupler, the first 15 and second 16 feedback resistors, and the output adder 17.,

The DC voltage amplifier 35 with galvanic isolation works as follows.

When an input signal voltage is applied to the input, it enters simultaneously the input of the input amplifier 3 40 of the first channel 1 and the input of the second channel 2, where νοΜΠΗΒββτοΗ is the last with the gain K and goes to the second input of the output adder 17 and simultaneously to the input of the additional 45th modulator 11 , is converted last to modulated voltage and enters the primary winding of an additional decoupling transformer 10. At the same time, from the output of an input amplifier 3 having a gain also equal to K, the input amplifier The voltage supplied to the input of the modulator 4, where it is converted to a modulated voltage 55 and transmitted to the primary winding of the isolation transformer 5. Due to the fact that the windings of these transformers are turned on, there is no voltage proportional to the input signal in the secondary winding of the isolation transformer 5, t .e. at the output of the device there is a voltage proportional to the output signal of the second channel 2.

Thus, the first channel 1 in the transmission of the input signal to the output of the entire device is not involved, therefore, the dynamic characteristics of the entire device are determined only by the dynamic characteristics of the second channel 2.

If there is no bias voltage at the inputs of the modulator 4 and the additional modulator 11 in the output signal of the second channel 2, the voltages are not equal, and in the secondary winding of the isolation transformer 5 of the first. channel 1 there is a modulated voltage proportional to the bias voltage of the second channel 2, as a result of which it is demodulated, filtered and fed to the first input of the output adder 17 with a value equal to the bias voltage of the second channel 2, as a result, the voltage proportional to the input signal appears again at the output of the device . Due to the fact that the output voltage at the output of filter 8 is very small, the level of the combinational component is negligible, and when working with pulsed input signals, the dynamic error is significantly reduced. .

Claims (1)

Claim A DC voltage amplifier with galvanic isolation of the input and output, containing the first and second amplification channels, the inputs of which are combined and are the input of the DC voltage amplifier with galvanic isolation, the first amplification channel is made on a series-connected input amplifier, modulator, isolation transformer, demodulator, low-pass filter , a DC amplifier, and the second amplification channel is made on the first operational amplifier, a galvanic isolation element made on an optocoupler, the second operational amplifier, while the outputs of the amplification channels under 3 • 1376234 are connected to the corresponding inputs of the output adder, which differs in that, in order to reduce the dynamic error when working with pulsed signals, an additional modulator and an additional isolation transformer are introduced, the input of the additional modulator is connected to the output of the second operational amplifier of the second amplification channel, and the output to the primary winding of ^an additional> decoupling transformer, one output of the primary winding which is the other input of the DC amplifier with galvanic isolation, and the other terminal is connected to the corresponding terminal of the primary winding of the decoupling transformer of the first amplification channel. Order 797/55